Synchronized transport across non-synchronous networks

Details Synchronized transport across non-synchronous networks Synchronized transport across non-synchronous networks

2000-12-07

2004-06-08

Cangialosi, Salvatore (Department: 2661)

Multiplex communications

Communication techniques for information carried in plural...

Combining or distributing information via time channels

C370S516000

Reexamination Certificate

active

06747996

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to the field of communications, and, in particular, a network communications system wherein synchronized voice services are provided to a remote synchronous network over a non-synchronous shared medium LAN integrated with a gateway coupled to the remote synchronous network.
As computers become more and more cost effective for the everyday consumer and for small businesses, such computers become more plentiful for use within local area environments such as homes, office buildings and the like. For example, within a home a person with a computer in the bedroom, and another in the living room, may want to share common files, utilize a common digital subscriber line (DSL), or otherwise transfer information between the computers. Accordingly, various technologies are being developed for computer interconnection of multiple computers located within such environments. One example of such technologies is the Home Phoneline Network Alliance (HPNA) technology for Local Area Network (LAN) computer interconnection which utilizes existing telephone lines within the local environment for the transmission of data packets between the computers. The HPNA technology is implemented in the Broadcom Corporation Model Number BCM 4210 Controller product and is set forth in U.S. patent application Ser. No. 60/196,002 entitled “Home Phone Line Network and Apparatus”, the content of which is incorporated by reference herein.
FIG. 1
shows in block diagram form a general home networking environment within which the present invention can be implemented. Home network
10
includes existing (installed) plain old telephone service (POTS) wiring
12
, network clients
14
, the computer port side of modem
16
and fax
18
. POTS wiring
12
provides wiring infrastructure used to network multiple clients at a customer premises (e.g., home)
20
. POTS wiring
12
can be conventional unshielded twisted pair (UTP) wiring that is generally routed internally in the walls of the customer premises
20
to various locations (e.g., rooms) within the customer premises. Subscriber loop
22
(also called a “local loop”) is a physical wiring link that directly connects an individual customer premises
20
to the Central Office through telephone interface
24
, a demarcation point between the inside and outside of customer premises
20
. Of particular importance for residential networks are systems that provide communication between computers as reliably and with as high a data rate as possible. Communication over residential telephone wiring is provided through inventive frame-oriented link, media access and physical layer protocols and implementation techniques associated therewith.
Given the HPNA environment, an opportunity exists integration of the HPNA environment with voice services for transfer of voice message (from a caller) to a voice services recipient(a called party) over, for example, a cable modem system, or a Wide Area Network (WAN), or a Global Network such as the Public Switched Telephone Network (PSTN) or Internet Protocol (IP) Network.
FIG. 2
depicts such an integrated environment. As can be seen in
FIG. 2
, a connection point in the home to the telephony world (e.g., the world of video, voice, high speed data network traffic), could be provided to a home user through cable modem
30
which would include an HPNA transceiver. The cable modem system provider may also wish to accommodate providing telephone service along with high speed data service. A home computer user, rather than using a traditional modem to connect to an internet service provider, would find it convenient to utilize cable modem
30
, taking advantage of the very high speed data service provided by the cable modem. Having a cable modem customer, the cable modem provider may also find it commercially beneficial to offer video feeds, and telephone service over the same cable modem network. Cable modem
30
would be coupled to Headend
32
over Hybrid Fiber Coaxial (HFC) network
34
. Headend
32
would include internet router
36
having Cable Modem Termination System (CMTS)
38
for communication with the Internet. A CM/CMTS system can be implemented using the Broadcom Corporation Model Number BCM3210Cable Modem Termination System product and is described in detail in U.S. patent application Ser. No. 09/501,850 entitled “Cable Modem System with Sample and Packet Synchronization”, which is incorporated by reference herein.
Referring now to
FIG. 3
, there is shown a more simplified example of a voice services communications network, along with a depiction of the synchronous and asynchronous aspects associated with particular portions of the network. Telephone handset
40
is connected to terminal
42
which consists in part of: (a) voice codec
44
, which converts between analog signals and. sampled digital signals at a sample rate which is determined by a clock in the codec (hereinafter “Clock
2
”), and (b) HPNA network interface(I/F)
46
a
, which assembles the voice samples into a packet (e.g., such as a layer-2 frame type) which is then transmitted on HPNA network
48
to gateway
50
. Gateway
50
receives the HPNA packet at counterpart HPNA network I/F
46
b
and queues it for transmission by Wide Area Network (WAN) interface
52
. This transmission is made synchronous to a gateway clock (hereinafter “Clock
1
”) in gateway
50
which is determined by the access equipment at the other end of the DOCSIS link
56
, e.g., the CMTS, should gateway
50
be part of cable modem
30
as seen in FIG.
2
. Clock
1
is made synchronous in gateway
50
in accordance with the teachings of U.S. patent application Ser. No. 09/501,850 referenced above. The packet sent up WAN DOCSIS link
56
is routed across global Internet Protocol (IP) network
54
to the destination, e.g., a comparable gateway/terminal combination (or equivalent) to that of gateway
50
combined with terminal
42
. Similarly, voice packets received over the DOCSIS WAN link
56
by WAN I/F
52
, are transmitted by gateway HPNA I/F
46
b
over HPNA network
48
to terminal HPNA I/F
46
a
, where the packet is disassembled back into samples which are converted by voice codec
44
back into analog signals for telephone handset
40
. Included in
FIG. 3
is a depiction of information transition
60
from the DOCSIS domain (synchronous to Clock
1
) to the asynchronous HPNA network (which introduces some jitter), and transition
62
from the asynchronous HPNA network to the terminal voice codec domain (synchronous to Clock
2
).
A need therefore exists for a effective transport of synchronized voice services over a non-synchronous network. The present invention provides a solution to such need.
SUMMARY OF THE INVENTION
In accordance with the present invention a method is providing for synchronizing one or more synchronous terminals with one or more synchronous endpoints, each synchronous terminal and each synchronous endpoint having an asynchronous communications network coupled between at least one synchronous terminal and at least one synchronous endpoint. A synchronization protocol (SP) is established between a synchronous terminal and a synchronous end point by providing a gateway between the asynchronous communications network and the synchronous end point, the gateway communicating with the synchronous terminal over the asynchronous communications network in accordance with the synchronization protocol. The synchronization protocol includes sending a message (referred to herein as an “SP packet”) from the gateway to the synchronous terminal, the SP packet containing a timestamp identifying a clock associated with the synchronous end point. The synchronous terminal establishes a clock associated with the synchronous terminal by creating a clock estimate based upon the timestamp message and measurements of the access jitter introduced by the asynchronous communications network such that the clock associated with the synchronous terminal enables packet sampling and transmission onto the asynchronous communications netwo

Affiliated with

Also associated with

Rating

Synchronized transport across non-synchronous networks does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Synchronized transport across non-synchronous networks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Synchronized transport across non-synchronous networks will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3300658